1. Field of the Invention
This invention relates generally to an improved hinge assembly and, more particularly, to a hinge assembly which is suitable for use in connection with an electronic digital device.
2. Description of the Prior Art
Hinges, per se, are well-known in the prior art. It is well known, for example, that prior hinges may be used to fasten two members to allow them to move from a first position to other positions in which one member has moved relative to the other. A door and its pivotal connector to a door frame provides a very common example of a hinge. Hinges, however, are used in many applications, including in electronic digital devices such as digital computers and terminals.
Digital computers and terminals are also well known in the prior art and are commercially available from a number of manufacturers. Computers and terminals may be portable and those portable units commonly have a display section that has an adjustable viewing angle with respect to the base of the device. These prior art devices generally utilize a type of brake mechanism which is based upon sliding friction to provide the hinge's resistance to movement. Such a sliding frictional force is often developed and maintained through the use of metal springs in different sizes and shapes. Such brake mechanisms, because they utilize sliding friction, usually cause excessive wear to the hinge and are not particularly stable during hard vibrations. Moreover, the hinges utilizing brake mechanisms tend to provide a constantly degrading level of resistance as the hinge material is worn away through use. Another limitation of such hinge devices is that they are "hard mounted" which means that they provide no shock or vibrational protection to a portable computer or terminal. Vibrations may result from a number of sources, especially the means of transportation used when moving a portable electronic device, such as those which often result when the device is in a moving automobile, train, or airplane.
A number of prior art hinges have various disadvantages. Some hinges which are used in portable electronic devices leave a large amount of free play before any resistance is felt by the user. Other types of hinges tend to develop a dragging or scratching which is felt by the user and may even become audible. Other hinges allow rotational movement of the members only in discrete steps through the use of a ratchet-type of mechanism or a detente. Therefore, if the optimal viewing angle for a particular user is between two discrete ratchet steps, the user must choose a position which is not optimal.